Microfabrication and nanofabrication techniques often require movement of micro-scale or nano-scale objects from one workstation to another, or for manipulating the position of an object within a workstation, typically in a clean-room environment that must be relatively dust free. Given the small size of the objects being formed and the need for precision movement, it is often necessary to move or arrange such objects with a robotic arm. Accordingly, the robotic arm must be able to engage such objects, transfer them to a second workstation, often at a precise location and orientation, and release the object once properly placed.
There are several possible gripping mechanisms that might be employed by the robotic arm, including mechanical, magnetic, or adhesive-type gripping. Mechanical gripping suffers from the problem that many objects cannot be readily gripped mechanically, or only with a risk of damaging the object. Additionally, a mechanical gripping mechanism may require end-effector lubricant that has the potential for contaminating the clean-room environment. Magnetic gripping avoids both of these problems, but is useful, of course, only where the objects being manipulated have suitable magnetic. Adhesive gripping provides an attractive alternative to mechanical or magnetic gripping, assuming that the adhesive bond allows for easy release of the object and does not contaminate the object with adhesive material, e.g., tacky polymer material. Heretofore, the inventor has been involved in the development of a gripping system that employs mechanisms of adhesion in gecko footpad setae for use in gripping and transporting objects. See, for example, U.S. patent application US 20030124312 A1, published Jul. 3, 2003, and incorporated herein by reference. Briefly, the gripping mechanism described in this application includes an array of gecko setae or artificially constructed setae that have essentially the same adhesive properties as the gecko foot pad. The array can form a strong adhesive bond to objects upon contact, allowing the objects to be gripped at one location and picked up and moved to another location. Once placed at its destination, the object can be released from the gripping head by angulating the head to “strip” the object away.
One limitation of the above system is that small particles, such as dust, are also picked up and transported by the gripping head, and this has the potential to contaminate the objects being moved.
It would therefore be desirable to provide a gripping-transporting mechanism that can be maintained in a substantially dust-free state during operation, thus avoiding problems of dust contamination in a setting, such as a clean room setting, where avoiding particle contamination is essential. It would also be desirable, for nanotechnology application, to provide a system that is capable of moving and placing nano-scale objects within a workstation.